地点：机械楼302会议室

欢迎有兴趣的老师和研究生参加。

Abstract:  The
transmission efficiency of a precision gear system can be very high,
particularly the meshing efficiency of a pair of spur gears, which can reach
above 99.5%. Nevertheless, any designs that can further improve the energy
efficiency can still be significant for high-power, multistage transmissions.
Because of the high efficiency, it can be very difficult to determine accurate
values of the percentage power losses either in laboratory experiment or by
theoretical modeling. The task is further complicated if the loss in the gear
system is to be separated into various components such as meshing, spinning and
bearing losses.

In the author’s opinion, it is the trends and relative
magnitudes of the percentage losses with respect to parameter variations that
play the key role in the gear design and lubricant selection to further improve
transmission efficiency. These trend and relative-magnitude results may be
obtainable without the need to obtain exceedingly accurate power-loss results
which are limited by experimental resolution and/or modeling imperfection. A
lean first-principle based modeling appears to be the best for this task as the
results are not contaminated by measurement scatters inherited in the
experiments or hard-to-trace uncertainties associated with the parameter-laden
empirical formulas. This work aims to develop such a first-principle based
model focusing on meshing efficiency of involute spur gears. The model is
fundamentally simple with a few clearly defined physical parameters so that the
cause-and-effect results produced by the model can be easily traced and
evaluated. The accuracy of the model is evaluated against well documented
experimental data. Subsequently, it is used to study the trends and relative
magnitudes of the meshing losses with respect to the variations of a few key
parameters that describe gear design and lubricant property. The results
suggest that gear module, pressure angle, and lubricant pressure-viscosity and
temperature-viscosity coefficients can significantly affect the meshing losses.
Although the model is developed and results obtained for spur gears, we believe
that the trends and relative magnitudes of the meshing losses with respect to
the variations of the gear and lubricant parameters are still meaningful for
helical gears.

机电工程与自动化学院